This invention relates to derivatives of the furo[3,2-f]-1,2-benzosoxazole ring system; specifically, compositions for the treatment of hypertension, cardiac failure, edema, and other conditions involving fluid or electrolyte Accumulation. A highly versatile synthetic process for the preparation of these substances is described, as well as a diuretic composition in dosage unit form.
Derivatives of the fully aromatic furobenzisoxazole system have been previously disclosed and have shown a variety of applications stemming from their biological activity. In the Journal of the Indian Chemical Society, Vol. 54, No. 9, pp. 875-877 (1977), and in the Indian Journal of Chemistry, Vol. 1513, No. 11, pp. 1058-1059 (1977), Thakar et al. describe some dialkyl derivatives with antifungal activity. Methyl derivatives in the 3- position were also reported by Hismat et al. in Zeitschrift fur Naturforschung, Vol. 336, pp. 1491-1495 (1978), as being obtained from the natural products visnaginone and khellinone. these syntheses, however, make no provision for variation of the substituents in the 6 and 8 positions and are relatively inflexible as regards the 3-substituent. They do not afford the substitution pattern herein described.
The object of this invention is to provide compositions of utility as diuretic agents, and to provide a general synthesis of these and other related compounds.